Hermetically sealed shipping package and method of preparing same

ABSTRACT

A hermetically sealed shipping container particularly suitable for shipping hazardous liquids is formed by placing the liquid containers on a tray, wrapping the tube and containers in a longitudinally sealed tube of monoaxially oriented and heatshrinkable film with the film extending beyond the ends of the tray, shrinking the film tightly around the containers and tray, and thereafter applying clips to the shrunken tube openings at either end of the package to seal the package. The resulting package holds the containers securely in place, is impervious to liquids, and is resistent to acids, bleaches, or the like.

United States Patent Thompson et a1.

HERMETICALLY SEALED SHIPPING PACKAGE AND METHOD OF PREPARING SAMEInventors: Henry Bryan Thompson, Duncan;

Jerry Lee Mautz, Greenville, both of S.C.

Assignee: W. R. Grace & Co., Duncan, S.C.

Filed: Jan. 21, 1971 Appl. No.: 108,509

US. Cl. 206/65 S, 206/45.33, 229/D1G. 12, 206/65 E Int. Cl B6Sd 65/16,B6Sd 85/62 Field of Search 206/65 S, 65 E, 45.33; 229/65, DIG. 12;215/38 A References Cited UNITED STATES PATENTS Kirkpatrick et al229/D1G. l2

[ July 17, 1973 3,358,902 12/1967 Emmert et a1. 215/38 A PrimaryExaminerWilliam T. Dixson, Jr. Attorney-John J. Toney, William D. Lee,Jr. and Edward J. Hanson, Jr.

[57] ABSTRACT A hermetically sealed shipping container particularlysuitable for shipping hazardous liquids is formed by placing the liquidcontainers on a tray, wrapping the tube and containers in alongitudinally sealed tube of monoaxially oriented and heat-shrinkablefilm with the film extending beyond the ends of the tray, shrinking thefilm tightly around the containers and tray, and thereafter applyingclips to the shrunken tube openings at either end of thepackage to sealthe package. The resulting package holds the containers securely inplace, is impervious to liquids, and is resistent to acids, bleaches, orthe like.

6 Claims, 3 Drawing Figures Patnted July 17, 1973 3,746,160

2 Sheets-Sheet 1 INVENTORSI HENRY B. THOMPSON JERRY MAUTZ ATT RNEYPatented July 17,1973

2 Sheets-Sheet 2 HERMETICALLY SEALED SHIPPING PACKAGE AND METHOD OFPREPARING SAME FIELD OF THE INVENTION This invention relates toindustrial shipping packages or containers. Specifically, this inventionrelates to shipping packages for transporting a plurality of containersor bottles containing hazardous liquids such as acids, bleaches, orsolvents.

BACKGROUND OF THE INVENTION Because of their unique properties, the heatshrinkable thermoplastic films have attracted a greal deal of attentionin packaging applications. These films are generally those made frompolyvinylidene chloride, irradiated polyethylene, polyvinyl chloride,and polypropylene. Such films can be wrapped about objects, sealed, andthen shrunken tightly about the objects to form neat, wrinkle freepackages which hold the objects securely in place. If a package iscompletely sealed, it is customary in the prior art to provide a deflatehole in the film so that when it is shrunken the entrapped air mayescape. If no provision is made for the escape of air, obviously, theentrapped air will give the film a balloon-like appearance as the filmattempts to shrink under the influence of heat. The presence of adeflate hole allows any liquids or gases emitted from any of thearticles contained within the package to escape. Accordingly, it is anobject of the present invention to provide a package from heat shrunkenfilm which is hermetically sealed and free from any holes or aperatures.

An early prior art example of packaging a single object in monoaxiallyoriented, heat shrinkable, rubber hydrochloride film is found in thepatent to Curry, U.S. Pat. No. 2,878,628. In the Curry patent, the filmis formed in a tube, sealed longitudinally, and then shrunken leavingthe ends of the package open. A prior art example in which a pluralityof objects is packaged and held securely together is disclosed in thepatent to Dreyfus, U.S. Pat. No. 3,215,266. In the Dreyfus patent,biaxially oriented polyethylene film is formed in a tube around eitheran object or a collection of objects, and the tube is shrunken tightlyaround the objects to hold them securely in place. However, in theDreyfus patent as well as in the Curry patent the ends of the packageare left open.

In addition to using the tension forces in heat shrunken film to hold aplurality of objects securely together, prior art packages have alsoused, in combination with the shrunken film, trays and protectivepartitions to make shipping containers for a plurality of objects suchas a case of bottles. One example of such a package is shown in thepatent to Farquhar, U.S. Pat. No. 3,416,653, wherein a plurality ofbottles are placed in a supporting carton and overwrapped with a heatshrinkable film which tends to hold the bottles securely in place. Stillanother example is found in the patent to Ayer, U.S. Pat. No. 3,425,544,wherein a case of bottles or cans are placed on a tray with partitionsextending the height of the bottles to protect them. In addition, thebotles are held tightly in place by a shrunken film overwrap. However,in neither the Farquhar or Ayer patent are the ends of the packagesealed. Thus, it is another object of the present invention to provide apackage which has the advantages provided by partitioned trays andshrunken film overwrap and at the same time is hermetically sealed. Theaccomplishment of this and other objects will be understood from thefollowing description of the invention.

SUMMARY OF THE INVENTION In its broadest aspect, the present inventionis a hermetically sealed shipping package comprising at least oneobject, a tube of heat shrunken monoaxially oriented film tightlyenclosing said object, and a seal or closure means hermetically sealingeach end of the tube. In a more limited aspect, the present inventioncomprises a plurality of objects disposed on a supporting member with atube of heat shrunken monoaxially oriented film securely holding saidobjects on the supporting member and a closure means at each end of saidtube hermetically sealing the tube. The supporting member may be a traywith dividers to separate the objects and provide load carrying supportfor vertical stacking of the packages. The closure means can be a sealsuch as a heat seal which fuses the end of the tube together; or,preferably the closure can be a mechanically applied clip.

In its broadest aspect, the process of the present invention comprisesthe steps of enveloping at least one object in a tube of monoaxiallyoriented film wherein the film is positioned so that the radius of saidtube decreases upon heat shrinking, each end of the tube extendingbeyond the object so that sufficient film mate rial is provided to closethe tube and seal same; heat shrinking said tube so that it tightlycontacts said object; and thereafter sealing each end of said tube. In amore limited aspect, the method of the present invention comprisesplacing a plurality of objects on a supporting member and then enclosingsaid objects in a tube of monoaxially oriented film and thereaftershrinking said tube about said objects and sealing each end of saidtube. A seamless tube can be used, or a tube may be made by'sealingtogether the two ends of a sheet of film. A preferred film for theinvention is monoaxially oriented, cross-linked polyethylene film; or,also preferred is polyvinyl chloride film.

DESCRIPTION OF THE DRAWINGS In the accompanying drawings:

FIG. 1 is a perspective representation of one embodiment of a packageaccording to the present invention;

FIG. 2 is a schematic representation of one step in making a packageaccording to the present invention; and,

FIG. 3 is a schematic representation of another step in preparing apackage according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. I, acompleted package I according to the present invention is seen. Thispackage comprises the shrunken film tube 2, a supporting member or tray3, closure means or clips 4, a stacking divider 5 for carrying verticalloads when the packages are stacked, and a plurality of objects orbottles 6.

Looking now at FIG. 2, a plurality of objects 6 is shown on supportingmember 3 enveloped by the film tube 2 having end portion 7 thereofextending beyond the supporting member 3 and objects 6. Enveloping theobjects and supporting member as shown in FIG. 2 is one step in themethod of the present invention. The

film tube 2 can be a seamless tube or it can be formed by bringing theends of a sheet together and sealing same. It is essential that theorientation of the film be such that when heat is applied the radius ofthe tube will diminish without substantial decrease in the length of thetube. The reason for this is illustrated in FIG. 3 which shows the tubeof FIG. 2 after heat has been applied to shrink it and decrease itsradius. The objects 6 and. tray 3 enclosed in the shrunken tube 2 inFIG. 3 restrain, in their respective region, the shrinkage of the tubeand are thereby held tightly and securely in place. The unrestrainedportions 8 of the tube 2 which extend beyond the tray are shrunken andhave an appearance as shown. These end portions can be clipped togetherwith a mechanical clipper using metal or plastic clips or the ends couldbe fused and sealed with the application of heat. When sealed, thepackage is hermetically closed thus offering protection against theleakage from any of the products contained therein.

For the purposes of this invention, monoaxially oriented film means afilm which has been preferentially oriented in one direction only andthe orientation in the other direction is only consequential. This wouldmean that the film for tube 2 of FIGS. 2 and 3 is oriented radially sothat the radius of the tube decreases when the film is shrunk and thereis not enough longitudinal orientation to pull the ends of the film 7back to or over the tray 2, i.e. the longitudinal orientation issufficiently small so that the shrunken ends 8 of the tube have enoughfilm material so that the respective openings therein can close onthemselves.

A metal clip which can be mechanically applied to close the shrunkenopenings in the ends of the tube of the package in the present inventionis described in the patent to Tipper, US. Pat. No. 3,266,138. Theseclips are U-shaped and are forced around the gathered material by apunch and die. A complete apparatus for so fastening the clips isdescribed in another patent to Tipper, US. Pat. No. 3,210,835.

Preferred films for the present inention are monoaxially oriented filmprepared from polyethylene which has been cross-linked by irradiation orpolyvinyl chloride. The irradiated polyethylene is acid resistent,tough, and resists melting at elevated temperatures.

The package of this invention and the method for making the package maybe employed with various supporting members or trays and dividers withvertical load carrying ability. Even a single object without a supportmember can be hermetically shrink packaged by the present methodwhereas, in the prior art, hermetically sealed shrink packages couldonly be accomplished by rescaling or patching the deflate hole.

We claim:

1. A hermetically sealed shipping package comprismg:

a. a supporting member;

b. a plurality of objects carried by said supporting member;

0. a tube of heat shrunken, monoaxially oriented film securely holdingsaid objects on said supporting member, each end of said tube beingshrunken to cover the end areas of said package; and,

d. sealing means hermetically enclosing each end of said tube.

2. The package of claim 1 wherein the supporting member is a tray.

3. The shipping package of claim 2 wherein said tray has at least oneload carrying protective divider.

4. The shipping package of claim 1 wherein the film is cross-linked,monoaxially oriented polyethylene.

5. A process for making a hermetically sealed shipping package fromshrinkable film without a vacuum chamber or deflate hole in said filmcomprising the steps of:

a. placing a plurality of objects on a supporting member;

b. enveloping said objects and said supporting member in a tube ofmonoaxially oriented film, said film being shrinkable so that the radiusof said tube decreases when heat is applied thereto, and each end ofsaid tube extending beyond the objects and the supporting member tocompletely cover both of same;

0. applying heat to said tube to shrink it tightly about said objectsand supporting member so that the ends of said package are enclosed;and,

d. hermetically sealing the ends of said tube.

6. The method of claim 5 wherein the tube is monoaxially oriented,cross-linked, polyethylene.

1. A hermetically sealed shipping package comprising: a. a supportingmember; b. a plurality of objects carried by said supporting member; c.a tube of heat shrunken, monoaxially oriented film securely holding saidobjects on said supporting member, each end of said tube being shrunkento cover the end areas of said package; and, d. sealing meanshermetically enclosing each end of said tube.
 2. The package of claim 1wherein the supporting member is a tray.
 3. The shipping package ofclaim 2 wherein said tray has at least one load carrying protectivedivider.
 4. The shipping package of claim 1 wherein the film iscross-linked, monoaxially oriented polyethylene.
 5. A process for makinga hermetically sealed shipping package from shrinkable film without avacuum chamber or deflate hole in said film comprising the steps of: a.placing a plurality of objects on a supporting member; b. envelopingsaid objects and said supporting member in a tube of monoaxiallyoriented film, said film being shrinkable so that the radius of saidtube decreases when heat is applied thereto, and each end of said tubeextending beyond the objects and the supporting member to completelycover both of same; c. applying heat to said tube to shrink it tightlyabout said objects and supporting member so that the ends of saidpackage are enclosed; and, d. hermetically sealing the ends of Saidtube.
 6. The method of claim 5 wherein the tube is monoaxially oriented,cross-linked, polyethylene.